/*
*
* Copyright (c) 2006-2011 Sam Collett (http://www.texotela.co.uk)
* Dual licensed under the MIT (http://www.opensource.org/licenses/mit-license.php)
* and GPL (http://www.opensource.org/licenses/gpl-license.php) licenses.
*
* Version 1.3.1
* Demo: http://www.texotela.co.uk/code/jquery/numeric/
*
*/
(function($) {
/*
* Allows only valid characters to be entered into input boxes.
* Note: fixes value when pasting via Ctrl+V, but not when using the mouse to paste
* side-effect: Ctrl+A does not work, though you can still use the mouse to select (or double-click to select all)
*
* @name numeric
* @param config { decimal : "." , negative : true }
* @param callback A function that runs if the number is not valid (fires onblur)
* @author Sam Collett (http://www.texotela.co.uk)
* @example $(".numeric").numeric();
* @example $(".numeric").numeric(","); // use , as separator
* @example $(".numeric").numeric({ decimal : "," }); // use , as separator
* @example $(".numeric").numeric({ negative : false }); // do not allow negative values
* @example $(".numeric").numeric(null, callback); // use default values, pass on the 'callback' function
*
*/
$.fn.numeric = function(config, callback)
{
        if(typeof config === 'boolean')
        {
                config = { decimal: config };
        }
        config = config || {};
        // if config.negative undefined, set to true (default is to allow negative numbers)
        if(typeof config.negative == "undefined") { config.negative = true; }
        // set decimal point
        var decimal = (config.decimal === false) ? "" : config.decimal || ".";
        // allow negatives
        var negative = (config.negative === true) ? true : false;
        // callback function
        callback = (typeof(callback) == "function" ? callback : function() {});
        // set data and methods
        return this.data("numeric.decimal", decimal).data("numeric.negative", negative).data("numeric.callback", callback).keypress($.fn.numeric.keypress).keyup($.fn.numeric.keyup).blur($.fn.numeric.blur);
};

$.fn.numeric.keypress = function(e)
{
        // get decimal character and determine if negatives are allowed
        var decimal = $.data(this, "numeric.decimal");
        var negative = $.data(this, "numeric.negative");
        // get the key that was pressed
        var key = e.charCode ? e.charCode : e.keyCode ? e.keyCode : 0;
        // allow enter/return key (only when in an input box)
        if(key == 13 && this.nodeName.toLowerCase() == "input")
        {
                return true;
        }
        else if(key == 13)
        {
                return false;
        }
        var allow = false;
        // allow Ctrl+A
        if((e.ctrlKey && key == 97 /* firefox */) || (e.ctrlKey && key == 65) /* opera */) { return true; }
        // allow Ctrl+X (cut)
        if((e.ctrlKey && key == 120 /* firefox */) || (e.ctrlKey && key == 88) /* opera */) { return true; }
        // allow Ctrl+C (copy)
        if((e.ctrlKey && key == 99 /* firefox */) || (e.ctrlKey && key == 67) /* opera */) { return true; }
        // allow Ctrl+Z (undo)
        if((e.ctrlKey && key == 122 /* firefox */) || (e.ctrlKey && key == 90) /* opera */) { return true; }
        // allow or deny Ctrl+V (paste), Shift+Ins
        if((e.ctrlKey && key == 118 /* firefox */) || (e.ctrlKey && key == 86) /* opera */ ||
         (e.shiftKey && key == 45)) { return true; }
        // if a number was not pressed
        if(key < 48 || key > 57)
        {
         var value = $(this).val();
                /* '-' only allowed at start and if negative numbers allowed */
                if(value.indexOf("-") !== 0 && negative && key == 45 && (value.length === 0 || parseInt($.fn.getSelectionStart(this), 10) === 0)) { return true; }
                /* only one decimal separator allowed */
                if(decimal && key == decimal.charCodeAt(0) && value.indexOf(decimal) != -1)
                {
                        allow = false;
                }
                // check for other keys that have special purposes
                if(
                        key != 8 /* backspace */ &&
                        key != 9 /* tab */ &&
                        key != 13 /* enter */ &&
                        key != 35 /* end */ &&
                        key != 36 /* home */ &&
                        key != 37 /* left */ &&
                        key != 39 /* right */ &&
                        key != 46 /* del */
                )
                {
                        allow = false;
                }
                else
                {
                        // for detecting special keys (listed above)
                        // IE does not support 'charCode' and ignores them in keypress anyway
                        if(typeof e.charCode != "undefined")
                        {
                                // special keys have 'keyCode' and 'which' the same (e.g. backspace)
                                if(e.keyCode == e.which && e.which !== 0)
                                {
                                        allow = true;
                                        // . and delete share the same code, don't allow . (will be set to true later if it is the decimal point)
                                        if(e.which == 46) { allow = false; }
                                }
                                // or keyCode != 0 and 'charCode'/'which' = 0
                                else if(e.keyCode !== 0 && e.charCode === 0 && e.which === 0)
                                {
                                        allow = true;
                                }
                        }
                }
                // if key pressed is the decimal and it is not already in the field
                if(decimal && key == decimal.charCodeAt(0))
                {
                        if(value.indexOf(decimal) == -1)
                        {
                                allow = true;
                        }
                        else
                        {
                                allow = false;
                        }
                }
        }
        else
        {
                allow = true;
        }
        return allow;
};

$.fn.numeric.keyup = function(e)
{
        var val = $(this).val();
        if(val && val.length > 0)
        {
                // get carat (cursor) position
                var carat = $.fn.getSelectionStart(this);
                var selectionEnd = $.fn.getSelectionEnd(this);
                // get decimal character and determine if negatives are allowed
                var decimal = $.data(this, "numeric.decimal");
                var negative = $.data(this, "numeric.negative");
                
                // prepend a 0 if necessary
                if(decimal !== "" && decimal !== null)
                {
                        // find decimal point
                        var dot = val.indexOf(decimal);
                        // if dot at start, add 0 before
                        if(dot === 0)
                        {
                                this.value = "0" + val;
                        }
                        // if dot at position 1, check if there is a - symbol before it
                        if(dot == 1 && val.charAt(0) == "-")
                        {
                                this.value = "-0" + val.substring(1);
                        }
                        val = this.value;
                }
                
                // if pasted in, only allow the following characters
                var validChars = [0,1,2,3,4,5,6,7,8,9,'-',decimal];
                // get length of the value (to loop through)
                var length = val.length;
                // loop backwards (to prevent going out of bounds)
                for(var i = length - 1; i >= 0; i--)
                {
                        var ch = val.charAt(i);
                        // remove '-' if it is in the wrong place
                        if(i !== 0 && ch == "-")
                        {
                                val = val.substring(0, i) + val.substring(i + 1);
                        }
                        // remove character if it is at the start, a '-' and negatives aren't allowed
                        else if(i === 0 && !negative && ch == "-")
                        {
                                val = val.substring(1);
                        }
                        var validChar = false;
                        // loop through validChars
                        for(var j = 0; j < validChars.length; j++)
                        {
                                // if it is valid, break out the loop
                                if(ch == validChars[j])
                                {
                                        validChar = true;
                                        break;
                                }
                        }
                        // if not a valid character, or a space, remove
                        if(!validChar || ch == " ")
                        {
                                val = val.substring(0, i) + val.substring(i + 1);
                        }
                }
                // remove extra decimal characters
                var firstDecimal = val.indexOf(decimal);
                if(firstDecimal > 0)
                {
                        for(var k = length - 1; k > firstDecimal; k--)
                        {
                                var chch = val.charAt(k);
                                // remove decimal character
                                if(chch == decimal)
                                {
                                        val = val.substring(0, k) + val.substring(k + 1);
                                }
                        }
                }
                // set the value and prevent the cursor moving to the end
                this.value = val;
                $.fn.setSelection(this, [carat, selectionEnd]);
        }
};

$.fn.numeric.blur = function()
{
        var decimal = $.data(this, "numeric.decimal");
        var callback = $.data(this, "numeric.callback");
        var val = this.value;
        if(val !== "")
        {
                var re = new RegExp("^\\d+$|^\\d*" + decimal + "\\d+$");
                if(!re.exec(val))
                {
                        callback.apply(this);
                }
        }
};

$.fn.removeNumeric = function()
{
        return this.data("numeric.decimal", null).data("numeric.negative", null).data("numeric.callback", null).unbind("keypress", $.fn.numeric.keypress).unbind("blur", $.fn.numeric.blur);
};

// Based on code from http://javascript.nwbox.com/cursor_position/ (Diego Perini <dperini@nwbox.com>)
$.fn.getSelectionStart = function(o)
{
        if (o.createTextRange)
        {
                var r = document.selection.createRange().duplicate();
                r.moveEnd('character', o.value.length);
                if (r.text === '') { return o.value.length; }
                return o.value.lastIndexOf(r.text);
        } else { return o.selectionStart; }
};

// Based on code from http://javascript.nwbox.com/cursor_position/ (Diego Perini <dperini@nwbox.com>)
$.fn.getSelectionEnd = function(o)
{
        if (o.createTextRange) {
                var r = document.selection.createRange().duplicate()
                r.moveStart('character', -o.value.length)
                return r.text.length
        } else return o.selectionEnd
}

// set the selection, o is the object (input), p is the position ([start, end] or just start)
$.fn.setSelection = function(o, p)
{
        // if p is number, start and end are the same
        if(typeof p == "number") { p = [p, p]; }
        // only set if p is an array of length 2
        if(p && p.constructor == Array && p.length == 2)
        {
                if (o.createTextRange)
                {
                        var r = o.createTextRange();
                        r.collapse(true);
                        r.moveStart('character', p[0]);
                        r.moveEnd('character', p[1]);
                        r.select();
                }
                else if(o.setSelectionRange)
                {
                        o.focus();
                        o.setSelectionRange(p[0], p[1]);
                }
        }
};

})(jQuery);
